Ex-situ characterization and simulation of density fluctuations evolution during sintering of binder jetted 316L
Journal article, 2024

Efficient density evolution during sintering of the as-printed component is vital to reach full densification and required properties of binder jet (BJT) components. However, due to the high porosity and brittle nature of the green compact, analysis of the microstructure development during sintering is very difficult, resulting in lack of understanding of the densification process. Density development from green state (57 ± 1.6 %) up to full density (99 ± 0.3 %) was characterized by high-resolution synchrotron X-Ray computed tomography (SXCT) on BJT 316L samples from ex-situ interrupted sintering tests. Periodicity of density fluctuations along the building direction was revealed for the first time and was related to the layer thickness of ∼ 42 µm during printing that decreased down to ∼ 33 µm during sintering. Sintering simulations, utilizing a continuum sintering model developed for BJT, allowed to replicate the density evolution during sintering with a mean error of 2 % and its fluctuation evolution from green (1.66 %) to sintered (0.56 %) state. Additionally, simulation of extreme particle size segregation (1 µm to 130 µm) suggested that non-optimized printing could lead to undesirable density fluctuation amplitude rapid increase (∼10 %) during sintering. This might trigger the nucleation of defects (e.g., layer delamination, cracking, or excessive residual porosity) during the sintering process.

FEM simulation

Synchrotron X-Ray CT

Additive manufacturing

Binder Jetting

Sintering

Author

Alberto Cabo Rios

Chalmers, Industrial and Materials Science, Materials and manufacture

San Diego State University

T. Mishurova

Federal Institute for Materials Research and Testing

Laura Cordova Gonzalez

Chalmers, Industrial and Materials Science, Materials and manufacture

Mats Persson

Digital Metal

G. Bruno

Federal Institute for Materials Research and Testing

University of Potsdam

Eugene Olevsky

University of California

San Diego State University

Eduard Hryha

Chalmers, Industrial and Materials Science, Materials and manufacture

Materials and Design

0264-1275 (ISSN) 1873-4197 (eISSN)

Vol. 238 112690

Subject Categories

Materials Chemistry

Other Materials Engineering

Metallurgy and Metallic Materials

DOI

10.1016/j.matdes.2024.112690

More information

Latest update

2/9/2024 9